1. Field of the Invention
The present invention relates to a fuse assembly.
2. Description of the Related Art
In a vehicle as a moving body, there are various transmission lines for transmitting electric power, signals and so on, such as busbars contained in an electricity connection box such as a junction block, relay box, fuse block, terminals of electrical connector, etc.
In the above described transmission lines, there have been used fuse blocks provided with a number of detachable fuses for protecting electric circuits of various types of electric equipments from breakdown. Since the fuse block may include relays and busbars, the fuse block is also called as a relay box or a junction block, or generally called as an electricity connection box. In this specification, the fuse block, relay box, junction box will be hereinafter called as the connection box in general.
Conventionally, a fuse assembly 51 as shown in FIG. 4 has been used as the fuse to be used in the connection box. As shown in FIGS. 4 and 5, the fuse assembly 51 consists of a pair of terminals 52 arranged in parallel to each other, a housing 54 which contains one end portions 53 of these terminals 52, and a fusible body 55 integrally formed with the terminals 52 and bridging the terminals 52.
Each of the terminals 52 is a blade-like member as shown in FIG. 5 and formed of electro-conductive metal. A plurality of through holes 56 are formed in the terminals 52 so as to extend through a matrix composing the terminals 52. The terminals 52 illustrated in FIGS. 4 and 5 are respectively provided with two through holes 56 arranged in a longitudinal direction. The two through holes 56 are provided both in middle parts 57 of the respective terminals 52 and at positions adjacent to the one end portion 53 thereof.
Respective other end portions 58 of the terminals 52 are electrically connected to receiving terminals or so in the aforesaid connection box, when the fuse assembly 51 is contained in the connection box. One of the receiving terminals is supplied with power from an electric source or so, while various loads are electrically connected to the other of the receiving terminals.
Accordingly, one of the terminals 52 is supplied with the power through the receiving terminal, while, to the other of the terminals 52, are connected the various loads. The one end portions 53 of the terminals 52 are contained in the housing 54 in a state where their inner faces 61 are opposed to each other.
The housing 54 is formed in a box-like shape and molded of insulating synthetic resin. The housing 54 defines therein a cavity for containing the one end portions 53 of the terminals 52. The housing 54 is provided with projections (not shown) which are adapted to be respectively engaged in the aforesaid through holes 56. When the projections are brought into engagement with the through holes 56, the terminals 52 are fixed to the housing 54.
The fusible body 55 interconnects the terminals 52, as shown in FIG. 5. Both ends of the fusible body 55 are respectively connected to the inner faces 61 of the terminals 52 located at the middle parts 57 of the terminals 52. The fusible body 55 has a fuse portion 62 which is adapted to be fused when amperage of the electric power supplied through one of the terminals 52 has exceeded a threshold value. The fuse portion 62 is formed by designing a middle part of the fusible body 55 to be smaller in its sectional area.
The fuse assembly 51 having the above described structure and installed in the connection box is adapted to stop the supply of the electric power to the aforesaid loads, as the fuse portion 62 is fused when the amperage of the power supplied to one of the terminals 52 via the aforesaid one of the receiving terminals has exceeded the threshold value.
In the conventional fuse assembly 51 as illustrated in FIG. 4, the fusible body 55 is connected to the middle parts 57 of the terminals 52. For this reason, when the fusible body 55 is heated by an overcurrent, the heat generated in the fusible body 55 is easily conducted to the other end portions 58 of the terminals 52.
In other words, in the conventional fuse assembly 51, the heat generated in the fusible body 55 has been likely to be conducted to the receiving terminals in the connection box as an external apparatus which are connected to the terminals 52. When the heat has been conducted to the receiving terminals, a casing of the connection box formed of insulating synthetic resin or the like may be undesirably deformed.
Moreover, because in the conventional fuse assembly 51, the through holes 56 are formed in the terminals 52, the fusible body 55, especially the fuse portion 62 is likely to vibrate due to vibrations or a sudden acceleration during driving, etc. of an automobile in which the connection box is installed.
Particularly, in case where the fusible body 55 is heated, there has been a fear that the fusible body 55 may be broken as a result of fatigue failure which has occurred at jointed parts with the terminals 52 due to the above described vibrations or so. In this case, the fusible body 55 will be detached from the terminals 52. As described, in the conventional fuse assembly 51, even though the amperage of the power supplied to one of the terminals 52 has not exceeded the threshold value, the electrical connection between the pair of the terminals 52 may sometimes be interrupted.
In view of the above, an object of the present invention is to provide a fuse assembly in which the heat conducted to the equipments connected to the terminals can be restrained, and which is free from interruption of the electrical connection between the terminals in case where the amperage is not above the value at which the fusible body is fused.
In order to attain the above described object, there is provided, according to the present invention, a fuse assembly comprising a pair of terminals which are arranged in parallel to each other, a housing having a cavity for containing one end portions of the terminals, and a fusible body interconnecting the terminals, wherein the fuse assembly is provided with anchoring parts for mounting the fusible body to the housing.
According to another aspect of the invention, each of the anchoring parts includes a through hole passing through the fusible body, and a projection projected from an inner wall of the housing defining the cavity, the projection being adapted to be engaged in the through hole.
According to a further aspect of the invention, the fusible body includes supporting portions which are respectively connected to end faces positioned at the one end portions of the terminals, and the through holes being formed in the supporting portions.
According to a still further aspect of the invention, the fuse assembly further includes second anchoring parts for respectively mounting the terminals to the housing, and the through holes are provided at ends of the supporting portions remote from the end faces of the terminals.
According to the first aspect of the invention, because the fusible body is fixed to the housing by means of the anchoring parts, the heat generated in the fusible body is conducted to the housing via the anchoring parts, and the fusible body will not easily vibrate when subjected to vibrations or sudden acceleration of an automobile.
According to the second aspect of the invention, because the anchoring parts include the through holes passing through the fusible body and the projections to be engaged in the through holes, the heat generated in the fusible body is conducted to the housing by way of the through holes and the projections, and the fusible body can be more reliably fixed to the housing.
According to the third aspect of the invention, because the through holes are provided in the supporting portion of the fusible body connected to the end faces of the terminals, the heat generated in the fusible body is easily conducted to the housing before conducted to the equipments connected to the terminals.
According to the third aspect of the invention, because the through holes are provided at the ends of the supporting portions remote from the end faces of the terminals, the heat generated in the fusible body is more easily conducted to the housing before conducted to the equipments connected to the terminals.